Spatial Control of Proton Pump H,K-ATPase Docking at the Apical Membrane by Phosphorylation-coupled Ezrin-Syntaxin 3 Interaction
| Autor: | Shige H. Yoshimura, Dongmei Wang, Huijuan Yu, Nerimiah Emmett, William W. Yao, Vincent C. Bond, Kunio Takeyasu, Ya Liu, Yuki Suzuki, Xiao Yuan, Xia Ding, Jiajia Zhou, Xuebiao Yao, Yin Zhang, Hirohide Takahashi |
|---|---|
| Rok vydání: | 2014 |
| Předmět: |
inorganic chemicals
macromolecular substances Biology environment and public health Biochemistry Exocytosis H(+)-K(+)-Exchanging ATPase Ezrin Parietal Cells Gastric Cell polarity medicine Animals Phosphorylation Protein kinase A Molecular Biology Cells Cultured Parietal cell Qa-SNARE Proteins digestive oral and skin physiology Cell Membrane Cell Biology Apical membrane Syntaxin 3 Protein Structure Tertiary Cell biology enzymes and coenzymes (carbohydrates) Cytoskeletal Proteins Protein Transport medicine.anatomical_structure Rabbits |
| Zdroj: | Journal of Biological Chemistry. 289:33333-33342 |
| ISSN: | 0021-9258 |
| Popis: | The digestive function of the stomach depends on acidification of the gastric lumen. Acid secretion into the lumen is triggered by activation of a cAMP-dependent protein kinase (PKA) cascade, which ultimately results in the insertion of gastric H,K-ATPases into the apical plasma membranes of parietal cells. A coupling protein is ezrin whose phosphorylation at Ser-66 by PKA is required for parietal cell activation. However, little is known regarding the molecular mechanism(s) by which ezrin operates in gastric acid secretion. Here we show that phosphorylation of Ser-66 induces a conformational change of ezrin that enables its association with syntaxin 3 (Stx3) and provides a spatial cue for H,K-ATPase trafficking. This conformation-dependent association is specific for Stx3, and the binding interface is mapped to the N-terminal region. Biochemical analyses show that inhibition of ezrin phosphorylation at Ser-66 prevents ezrin-Stx3 association and insertion of H,K-ATPase into the apical plasma membrane of parietal cells. Using atomic force microscopic analyses, our study revealed that phosphorylation of Ser-66 induces unfolding of ezrin molecule to allow Stx3 binding to its N terminus. Given the essential role of Stx3 in polarized secretion, our study presents the first evidence in which phosphorylation-induced conformational rearrangement of the ezrin molecule provides a spatial cue for polarized membrane trafficking in epithelial cells. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|